Cryptographic Vulnerabilities in Threshold Wallets. In the talk I will discuss threshold ecdsa signatures in the context of a wallet. In terms of cryptography this is a “wild wild west” and I will exemplify this using series of pitfalls and errors done by engineers and cryptographers, where eventually I show how a small misuse of cryptography broke an implementation of a threshold wallet completely. Finally I give some tools to implementers that wish to go down this path anyway. The talk is highly technical and low level but hopefully self contained. Breaking Bitcoin is an event for the technical community focusing on the security of Bitcoin and everything around it. Presentations aim to be technical, focusing on vulnerabilities, theorical or practical attacks targetting the users and the